Ionic liquid modified conductive two-dimensional material (at) MoS2 lubricating additive as well as preparation method and application thereof

Abstract

The invention discloses an ionic liquid modified conductive two-dimensional material (at) MoS2 lubricating additive and a preparation method and application thereof.The lubricating additive is characterized in that after amination modification is conducted on a conductive two-dimensional material with a few nanosheet layer surfaces containing hydroxyl, the conductive two-dimensional material reacts with a Mo source, MoS2 nanosheets evenly grow on the surface of the conductive two-dimensional material, and a core-shell composite structure is formed; the-S-S-bond of the lipoic acid ionic liquid is combined with the S vacancy in the MoS2 to obtain the MoS2 / S composite material. The ionic liquid modified Ti3C2Tx and MoS2 conductive polyurea lubricating grease prepared from the lubricating additive shows good antifriction and antiwear effects, and compared with a contrast, the friction coefficient is reduced by 51.0%, and the wear volume is reduced by 99.1%. Moreover, in a bearing electric corrosion test, the SSIL-Ti < 3 > C < 2 > T < x > (at) MoS2 nano additive shows a good electric corrosion inhibition effect.

Description

Technical Field

[0001] The present invention relates to a lubricating additive, in particular to an ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive, a preparation method thereof, and an application thereof. Background Art

[0002] With the advancement of high-speed and electrified industrial equipment, the problem of electro-corrosion caused by current leakage during operation in high-performance mechanical devices such as motor bearings, high-speed gears, and precision instruments has become increasingly prominent. Lubrication systems require not only excellent anti-friction and anti-wear properties but also excellent electro-corrosion suppression. To address these issues, traditional technical solutions involve modifying bearing design, shielding shaft currents with insulating coatings or ceramic bearings, or bypassing circuits to divert shaft currents. This requires customized designs for different bearings, which results in a waste of time, effort, and financial resources.

[0003] Conductive greases can mitigate galvanic corrosion by conducting electrical charges. Traditional conductive greases use conductive materials such as graphite and metal particles as additives. However, these greases suffer from unstable conductivity, poor friction reduction, and insufficient wear resistance. Under extreme operating conditions, these properties can lead to lubrication failure and increased wear of the metal substrate. Conventional greases struggle to meet the requirements for galvanic corrosion suppression, leading to the development of novel lubricant additives with superior overall performance.

[0004] In order to obtain conductive grease with anti-friction and anti-wear properties, friction reducers, anti-wear agents and conductive additives (such as metal particles, ionic liquids, graphite) are added to the base grease to improve the corresponding performance of the grease. x The material is a new type of two-dimensional transition metal carbide / nitride, which has a layered structure and intrinsic conductivity (>10 4 The layered structure and surface functionalization properties of Ti3C2T have been widely concerned. There are papers such as Tribology International 191 (2024) 109137 and other related works. x It has been studied as a conductive lubricating additive, but its interlayer stacking leads to insufficient active sites and its friction-reducing effect is average.

[0005] Due to its layered structure and good lubricity, a lot of work has introduced MoS2 as a friction reducer and anti-wear agent. Although the Chinese patent application number CN201410523263.0 uses MoS2 and other conductive additives to prepare conductive grease, it still physically blends multiple components as independent units. The Chinese patent application number CN201910268631.4 invented Ti3C2T x / MoS2 preparation method, but it is still a physical blending effect. The paper Adv. Funct. Mater. 2020, 30, 1910302 reported the core-shell structure of Ti3C2T x @MoS2, however, this is only true for multilayer Ti3C2T x Effective, single-layer Ti3C2T x It is not possible to grow MoS2 uniformly on its surface using this method.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention

[0007] The purpose of the present invention is to provide an ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive and its preparation method and application, which solves the problem that existing conductive greases are difficult to meet the requirements of electrical corrosion inhibition. It not only has friction reduction and anti-wear effects, but also exhibits good electrical corrosion inhibition effects.

[0008] In order to achieve the above-mentioned purpose, the present invention provides an ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive. The lubricating additive is obtained by amino-modifying a conductive two-dimensional material containing hydroxyl groups on the surface of a few-layer nanosheet, reacting with a Mo source to uniformly grow MoS2 nanosheets on the surface of the conductive two-dimensional material to form a core-shell composite structure, and then combining the -SS- bond of the lipoic acid ionic liquid with the S vacancy in MoS2.

[0009] Preferably, the amino modification is to react the conductive two-dimensional material with aminosilane to achieve amino modification on the surface of the conductive two-dimensional material; or / and, the preparation of the core-shell composite structure is to react the amino-modified conductive two-dimensional material with MoO4 in the Mo source under acidic conditions. 2- Through electrostatic interaction and hydrogen bonding, the MoS2 nanosheets are uniformly grown on the surface of the conductive two-dimensional material to form a core-shell composite structure; or / and, the thioctic acid ionic liquid is an ionic liquid formed by thioctic acid and 1-ethyl-3-methylimidazolium chloride; or / and, the conductive two-dimensional material is selected from GO, rGO, Ti3C2T x 、V2CT x 、Nb2CT x 、Ti2CT x and Mo2CT x Any one or two or more of the above.

[0010] A second object of the present invention is to provide a method for preparing the ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive, the method comprising the following steps: (1) aminosilane is mixed in an alcohol-water mixed solution under alkaline conditions, an aqueous solution of a conductive two-dimensional material containing hydroxyl groups on the surface of a few nanosheets is added, the reaction is carried out under reflux, and after the reaction is completed, post-processing is performed to obtain an amino-modified conductive two-dimensional material, and the amino-modified conductive two-dimensional material is dispersed in water to obtain an aqueous solution of the amino-modified conductive two-dimensional material; (2) mixing the aqueous solution of the amino-modified conductive two-dimensional material with a solution containing MoO4 2- The Mo source and thiourea reacted at 180±5 ℃ under acidic conditions to obtain a conductive two-dimensional material@MoS2 nanocomposite material; (3) The conductive two-dimensional material @MoS2 nanocomposite material and thioctic acid ionic liquid are ultrasonically dispersed in an aqueous solution at 30±5°C, and then stirred at room temperature to obtain an ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive.

[0011] Preferably, in step (1), the aminosilane comprises: KH550; or / and, in step (1), the alkaline condition is adjusted by ammonia water; or / and, in step (1), the amount of KH550 and the conductive two-dimensional material containing hydroxyl groups on the surface of the few-layer nanosheet is 4 mL:1200 mg; or / and, in step (1), the volume ratio of water to ethanol is 1:1; or / and, in step (1), the volume ratio of KH550 to the alcohol-water mixed solution is 1:100; or / and, in step (1), the reflux temperature is 70°C; or / and, in step (1), the conductive two-dimensional material containing hydroxyl groups on the surface of the few-layer nanosheet is selected from few-layer nanosheet Ti3C2T; or / and, in step (2), the acidic condition is adjusted by citric acid, and the Mo source is Na2Mo2 O4·2H2O, the mass ratio of Na2Mo2O4·2H2O, thiourea and citric acid is 2.9~3.0:4.2~4.3:0.2~0.3; or / and, in step (2), the Mo source is Na2Mo2O4·2H2O, the mass ratio of the amino-modified conductive two-dimensional material to Na2Mo2O4·2H2O is 1:3.9~4.0, and this ratio is too large or too small, which will lead to uneven material morphology; or / and, in step (2), the reaction time is 24 h; or / and, in step (3), the preparation method of the thioctic acid ionic liquid comprises: dissolving 1-ethyl-3-methylimidazolium chloride in ethanol, dissolving sodium hydroxide or potassium hydroxide in an ethanol solution, mixing the two solutions together, stirring at room temperature, removing sodium chloride or potassium chloride, and stirring and reacting with thioctic acid at room temperature to obtain the thioctic acid ionic liquid; or / and, in step (3), the mass ratio of the conductive two-dimensional material @MoS2 nanocomposite material and the thioctic acid ionic liquid is 1:1; or / and, in step (3), the stirring at room temperature is 24 h.

[0012] More preferably, the few-layer nanosheet Ti3C2T x The preparation method comprises: slowly adding Ti3AlC2 powder to a mixed solution of LiF and HCl, stirring at 35 ° C, and obtaining an etched Ti3C2T x The solution was centrifuged several times until the pH of the supernatant was close to 7; the precipitate was then collected, washed with ethanol, ultrasonically dispersed, centrifuged, and the precipitate was resuspended in water and centrifuged to obtain a few-layer nanosheet Ti3C2T x aqueous solution.

[0013] The third object of the present invention is to provide the use of the ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive in conductive grease.

[0014] The fourth object of the present invention is to provide an ionic liquid modified Ti3C2T x@MoS2 conductive polyurea grease, the conductive polyurea grease comprises: the ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive, and polyurea grease.

[0015] Preferably, the mass fraction of the ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive is 0.3~2.0 wt%; or / and, the polyurea grease is a polyurea grease with a thickener mass fraction of 8%; or / and, in the polyurea grease, the thickener is a polyurea formed by the reaction of 4,4'-methylenebis(phenyl isocyanate) with cyclohexylamine and octadecylamine; or / and, in the polyurea grease, the base oil comprises: any one or more of PAO8, PAO10 and PAO 20.

[0016] The fifth object of the present invention is to provide the ionic liquid modified Ti3C2T x A method for preparing @MoS2 conductive polyurea grease, the method comprising: The ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive is added to the polyurea grease, stirred at room temperature, and ground to obtain the ionic liquid modified Ti3C2T x @MoS2 conductive polyurea grease.

[0017] Preferably, the preparation method of the polyurea grease comprises: adding 4, 4'-methylenebis(phenyl isocyanate) to a base oil and continuously stirring at 60-70°C until completely dissolved to obtain a mixture A; adding cyclohexylamine and octadecylamine to the base oil and stirring thoroughly at 80-90°C to obtain a uniform mixture B; quickly adding the mixture B to the mixture A and reacting at 90°C, then heating the reaction system to 110-120°C and maintaining at this temperature, then increasing the temperature to 140-150°C and maintaining it, and after the reaction is completed, rapidly cooling and grinding to obtain the polyurea grease.

[0018] More preferably, the molar ratio of the 4,4'-methylenebis(phenyl isocyanate), cyclohexylamine and octadecylamine is 3:4:2; or / and, the 4,4'-methylenebis(phenyl isocyanate) is added to the base oil, and the ratio of the molar ratio of the 4,4'-methylenebis(phenyl isocyanate) to the mass of the base oil is 0.3 mol:1150 g; or / and, cyclohexylamine and octadecylamine are added to the base oil, and the ratio of the mass of the base oil to the molar amount of cyclohexylamine and octadecylamine is 575 g:0.2 mol:0.1 mol; or / and, the base oil comprises: any one or more of PAO8, PAO10 and PAO 20.

[0019] The sixth object of the present invention is to provide the ionic liquid modified Ti3C2T x@Application of MoS2 conductive polyurea grease in bearings.

[0020] The ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive of the present invention, its preparation method, and application solve the problem that existing conductive greases are difficult to meet the requirements for electrical corrosion inhibition, and have the following advantages: (1) The present invention is to Ti3C2T flake x The surface end groups were amino-treated and MoS2 was successfully grown on Ti3C2T through electrostatic interaction and hydrogen bonding. x The surface forms a uniform layer of Ti3C2T x @MoS2 nanomaterials, the -SS- bond of SSIL is combined with the S vacancy in MoS2 to successfully prepare SSIL-Ti3C2T x MoS2 nanomaterials. By adjusting the ratio of this additive to a polyurea grease composite system, a conductive grease with friction-reducing and anti-wear properties was prepared. This novel process is theoretically applicable to the uniform growth of MoS2 on all surfaces, as well as ionic liquid modification of MoS2.

[0021] (2) Ionic liquid modified Ti3C2T x @MoS2 conductive polyurea grease exhibits good friction reduction and anti-wear effects. Compared with the control, the friction coefficient decreased by 51.0% and the wear volume decreased by 99.1%. Moreover, in the bearing electrocorrosion test, SSIL-Ti3C2T x @MoS2 nano-additives exhibit good electro-corrosion inhibition;

[0022] (3) The present invention converts Ti3C2T x The few-layer nanosheets were treated with KH550 to have -NH2 end groups on their surface, which attracted the molybdenum source through electrostatic interaction and hydrogen bonding. MoS2 nanosheets were successfully grown uniformly on the surface of the few-layer MXene, forming a uniform core-shell composite structure, and a regular few-layer Ti3C2T x By modifying MXene@MoS2 with lipoic acid ionic liquid, a grease additive with significant wear reduction and anti-wear effects was developed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the preparation process of the ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive of the present invention.

[0024] Figure 2 The few-layer Ti3C2T prepared in Example 1 of the present invention x and few-layer Ti3C2T x @SEM image of MoS2 nanocomposite.

[0025] Figure 3 The present invention is a few-layer Ti3C2T x SEM image of unmodified MoS2 generated by direct reaction with Mo source.

[0026] Figure 4 SSIL-Ti3C2T prepared in Example 1 of the present invention x XPS pattern of @MoS2.

[0027] Figure 5 It is the friction coefficient COF of the comparative example and embodiment of the present invention.

[0028] Figure 6 The oil film state (a, c) and bearing electrical corrosion condition (b, d) of the comparative examples (a, b) and embodiments (c, d) of the present invention under an AC electric field are shown. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] Note: If specific conditions are not specified in the examples, the experiments were conducted under conventional conditions or those recommended by the manufacturer. Instruments used without manufacturer information are commercially available. Raw materials and reagents used without manufacturer information are commercially available or can be prepared by known methods.

[0031] Throughout this disclosure, all features, such as values, amounts, amounts, and concentrations, specified in numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to encompass and specifically disclose all possible subranges and individual values ​​within those ranges (including integers and fractions).

[0032] The features described in this disclosure may be combined in any manner, and as long as there are no conflicts between the combinations of these features, all possible combinations should be considered within the scope of this specification. Each feature disclosed in this specification may be replaced by any alternative feature that provides the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the features disclosed are merely general examples of equivalent or similar features.

[0033] The present invention provides an ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive and its preparation method and application, wherein the thioctic acid ionic liquid is used to modify the few-layer conductive two-dimensional material @MoS2, see Figure 1 , the preparation method thereof comprises: (1) A conductive two-dimensional material with few-layer nanosheet layers is prepared by chemical etching method, and the surface of the conductive two-dimensional material contains abundant hydroxyl groups; (2) In an aqueous solution, KH550 is used under alkaline conditions, and the conductive two-dimensional material is reacted with KH550 under heating conditions at 80 DEG C, so that the amino modification of the conductive two-dimensional material is successfully realized, and the amino-modified conductive two-dimensional material is collected by washing with water and alcohol and dissolved in an aqueous solution; (3) The surface of the amino-modified conductive two-dimensional material contains amino groups, and in a small amount of citric acid aqueous solution, the end group is protonated to exist in the form of -NH3 + , and MoO4 2- ions in sodium molybdate tend to gather around Ti3C2T x through electrostatic interaction and hydrogen bonding, which helps Mo source to gather and decompose on the surface of the conductive two-dimensional material and combine with S source, and further form a few-sheet conductive two-dimensional material @ MoS2 core-shell structure with regular morphology.

[0034] (4) 1-ethyl-3-methyl imidazolium chloride is dissolved in ethanol, an ethanol solution containing an equal amount of potassium hydroxide is added, potassium chloride is removed by filtration, and then an equal amount of thioctic acid is fully subjected to acid-base neutralization reaction to prepare thioctic acid ionic liquid, denoted as SSIL; (5) The conductive two-dimensional material @ MoS2 core-shell structure is combined with excess SSIL at room temperature through ultrasonic stirring, etc., and the -S-S- bond of SSIL is combined with the S vacancy in MoS2, so that the SSIL modified conductive two-dimensional material @ MoS2 material is successfully prepared.

[0035] The ionic liquid modified conductive two-dimensional material @ MoS2 lubricating additive of the application is compounded with a polyurea-based lubricating grease, and the addition ratio (0.3%~2%) of the ionic liquid modified conductive two-dimensional material @ MoS2 lubricating additive is adjusted to form a conductive polyurea lubricating grease with excellent lubricating performance and conductivity. Since SSIL, Ti3C2T x and MoS2 are a unified whole, the lubricating grease will release all of them at the friction interface, SSIL tends to preferentially adsorb on the surface of the friction pair, Ti3C2T x and MoS2 layers are easy to shear between layers, forming a unique nanostructure friction, which fully plays its load bearing, friction reducing and wear resistant, and conductive functions.

[0036] The ionic liquid modified conductive two-dimensional material @ MoS2 lubricating additive, its preparation method and application provided by the application are described in detail through the following examples and experimental examples.

[0037] Examples 1~4 The ionic liquid modified conductive two-dimensional material @ MoS2 lubricating additive is denoted as SSIL modified Ti3C2Tx @MoS2 is taken as an example, and its preparation method is as follows: (1) Ti3C2T x Preparation of few-layer nanosheets Stir 1.6 g LiF and 20 mL 9 M HCl solution in a polyphenylene ether beaker to ensure thorough mixing. Subsequently, slowly add 1 g Ti3AlC2 powder and stir in a 35 °C water bath for 24 h. x The solution was divided into two 50 mL centrifuge tubes. Centrifuged at 3500 rpm for several times until the pH of the supernatant was close to 7. The precipitate was then collected, washed with excess ethanol, and ultrasonically dispersed for 2 h using a 300W ultrasonic processor. Subsequently, the dispersion was centrifuged at 10000 rpm for 10 minutes to collect the precipitate. The precipitate was resuspended in 40 mL of deionized water and centrifuged at 3500 rpm for 10 min. Ti3C2T x The few nanosheets are on the upper part, and the upper black Ti3C2T x Aqueous solution was prepared with deionized water to a concentration of 20 mg / mL Ti3C2T x aqueous solution.

[0038] (2) Ti3C2T x Surface treatment of few-layer nanosheets 4 mL of KH550 was added to a mixture of 400 mL of deionized water and ethanol (water:ethanol volume ratio is 1:1). Next, 4 mL of ammonia water was added to create alkaline conditions and the mixture was stirred magnetically until completely homogeneous. After complete dissolution, 60 mL of Ti3C2T x The aqueous solution was added to the prepared KH550 solution and refluxed at 70 °C for 24 h. The resulting suspension was then centrifuged at 5000 rpm and washed three times with deionized water to ensure complete removal of unreacted KH550. The precipitated Ti3C2T x -NH3 was dispersed in 100 mL of aqueous solution and stored, and the measured concentration was 150 mg / mL.

[0039] (3) Few-layer Ti3C2T x Preparation of @MoS2 nanocomposites Take 5 mL of the above Ti3C2T xThe NH3 aqueous solution was diluted to 70 mL with deionized water and stirred evenly. 2.97 g Na2Mo2O4·2H2O, 4.26 g thiourea, and 0.27 g citric acid were added in sequence. After ultrasonic dispersion and magnetic stirring, the resulting uniform solution was transferred to a 100 mL tetrafluoroethylene-lined stainless steel autoclave and reacted at 180 °C for 24 h. After the reaction was completed, the solution was cooled, washed by centrifugation, and freeze-dried to obtain the few-layer Ti3C2T x @MoS2 nanocomposite material.

[0040] (4) Preparation of lipoic acid ionic liquid Dissolve 0.1 mol of 1-ethyl-3-methylimidazolium chloride in a small amount of ethanol and 0.1 mol of potassium hydroxide in an appropriate amount of ethanol. Mix the two solutions and stir at room temperature for 24 hours. Filter to remove the potassium chloride, then stir with 0.1 mol of lipoic acid at room temperature for 24 hours to fully neutralize the acid. The resulting solution is rotary evaporated and vacuum dried to prepare a lipoic acid ionic liquid, designated SSIL.

[0041] (5) SSIL modified few-layer Ti3C2T x @MoS2 nanocomposite Take 2 g of few-layer Ti3C2T x The Ti3C2T@MoS2 nanocomposite and 2 g SSIL were added to the aqueous solution and dispersed by ultrasonication at 750 W power and 30 ± 5 °C in a water bath for 2 h, followed by magnetic stirring at room temperature for 24 h. Finally, the Ti3C2T@MoS2 nanocomposite was washed by suction and freeze-dried to obtain the SSIL-modified Ti3C2T@MoS2 nanocomposite. x @MoS2, named SSIL-Ti3C2T x @MoS2.

[0042] SSIL modified Ti3C2T was prepared by using the conductive two-dimensional material @MoS2 lubricating additive modified by the above-mentioned ionic liquid. x @MoS2 conductive polyurea grease, comprising: the above-prepared ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive and polyurea grease, and the preparation method thereof is as follows: (1) Preparation of polyurea grease 0.6 mol of MDI (4, 4'-methylenebis(phenyl isocyanate)) was added to a 5.00 L stainless steel reactor containing 2300.00 g of PAO8 (hydrogenated polydecene) and stirred continuously at 60-70°C until completely dissolved. Similarly, 0.8 mol of cyclohexylamine (CA) and 0.4 mol of octadecylamine (OA) were added to 2300.00 g of PAO8 base oil and stirred thoroughly at 80-90°C to obtain a homogeneous mixture. Mixture B was then quickly added to Mixture A and allowed to react at 90°C for 1 hour. The reaction system was then heated to 110-120°C and maintained at this temperature for 1 hour, during which time additional CA was added to remove excess MDI. The temperature was then raised to 140-150°C and maintained for 30 minutes. After rapid cooling and grinding on a three-roll mill, a polyurea grease with an 8% thickener mass fraction was obtained.

[0043] (2) SSIL-modified Ti3C2T x Preparation of @MoS2 conductive polyurea grease Add a certain amount of SSIL-Ti3C2T to 8% polyurea grease x @MoS2 powder was manually stirred for 10 min at room temperature to ensure relatively uniform mixing, and then ground three times on a three-roll mill to obtain SSIL-Ti3C2T x Conductive polyurea greases with @MoS2 mass fractions of 0.3 wt%, 0.5 wt%, 1.0 wt% and 2.0 wt% are named MMSSIL-0.3, MMSSIL-0.5, MMSSIL-1.0, and MMSSIL-2.0, respectively, corresponding to Example 1, Example 2, Example 3, and Example 4.

[0044] Comparative Example The polyurea grease prepared in Example 1 with a thickener mass fraction of 8% was used as a comparative example.

[0045] Experimental Example 1 Structural Characterization 1. SEM For the few-layer Ti3C2T x and few-layer Ti3C2T x @SEM image of MoS2 nanocomposite material, by SEM ( Figure 2 ) analysis shows that the few-layer Ti3C2T x Successfully prepared, Ti3C2T x Direct growth of MoS2 without modification ( Figure 3 ), Ti3C2T prepared by the improved method x@MoS2 has a regular structure, and the wrinkled structure of MoS2 is clearly visible after magnification, proving that the few-layer Ti3C2T x @MoS2 nanocomposite materials were successfully prepared.

[0046] 2. XPS like Figure 4 As shown in the XPS analysis, the presence of C, N, O, Ti, Si, S and Mo elements in the total spectrum comes from Ti3C2T x , KH550 and MoS2, XPS analysis proves SSIL-Ti3C2T x @MoS2 was successfully prepared.

[0047] Experimental Example 2 Tribological Performance Test Tribological properties were evaluated over a 1 mm stroke using an SRV-V reciprocating friction and wear tester (Optimal Oil, Germany). The disc dimensions were 24 × 8 mm, with a surface roughness (Ra) of approximately 11 nm. The test conditions were: a load of 200 N, a frequency of 25 Hz, and a temperature of 50°C.

[0048] Table 1 Average friction coefficient and average wear volume of the examples

[0049] from Figure 5 As can be seen from Table 1, the friction coefficient of each embodiment is greatly improved compared with the comparative example. x @MoS2 showed good friction reduction effect, among which Examples 2 and 3 showed the most outstanding effect. In particular, the wear volume of Example 2 decreased by 99.1% compared with the control example, showing good anti-wear effect. This is mainly attributed to the fact that SSIL, Ti3C2T x and MoS2, which proves that the prepared SSIL-Ti3C2T x @MoS2 additives help improve the friction reduction and anti-wear effects of polyurea grease.

[0050] Experimental Example 3: Oil film state and bearing electrical corrosion protection performance test On the basis of ensuring friction reduction and anti-wear, choose SSIL-Ti3C2T with high addition x @MoS2 is used to improve the electrical corrosion prevention and control performance. The conductive polyurea grease MMSSIL-1.0 of Example 3 and the polyurea grease of the comparative example were tested for oil film state and bearing electrical corrosion protection performance, as follows: The oil film state was tested using a ball-on-disc tribometer at a rotational speed of 100 mm / s, a voltage of 10 V AC, and a power-on time of 1 minute. Red (~640 nm) and green (~525 nm) laser sources were used to observe the elastohydrodynamic lubrication (EHL) contact under a microscope. Interference images were captured using a high-speed CCD camera.

[0051] Bearing electrocorrosion tests were conducted on a test bench independently developed by the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences. The bearings used were 25 mm × 52 mm × 15 mm in size. The experimental conditions included a bearing speed of 3000 rpm, an applied alternating voltage of 11–14 V, a constant current of 23–24 A, and a run time of 6 hours.

[0052] from Figure 6 As can be seen from the figure, during the rotation of the bearing, the oil film formed by the comparative grease breaks down multiple times under the presence of shaft voltage, causing tip discharge and forming burn pits. Due to the unevenness, the damaged area is more likely to discharge repeatedly at the same location. Therefore, when the rotor rotates at high speed, the bearing undergoes a continuous charge and discharge breakdown process, forming a washboard pattern. For the conductive polyurea grease of Example 3, SSIL preferentially adsorbs on both sides of the bearing, driving the Ti3C2T x @MoS2 undergoes tribochemical reaction, where Ti3C2T x Both SSIL and SSIL have a certain degree of conductivity and are in a current-conducting state during operation. As the content of the prepared additives increases, the anti-electrocorrosion performance is significantly improved, thereby effectively improving the bearing electrocorrosion effect.

[0053] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. An ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive, characterized in that: The lubricating additive is obtained by amino-modifying a conductive two-dimensional material containing hydroxyl groups on the surface of a few-layer nanosheet, reacting with a Mo source to uniformly grow MoS2 nanosheets on the surface of the conductive two-dimensional material to form a core-shell composite structure, and then combining with the S vacancies in MoS2 through the -SS- bond of the thioctic acid ionic liquid.

2. The ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive according to claim 1, characterized in that The amino modification is to react the conductive two-dimensional material with aminosilane to achieve amino modification on the surface of the conductive two-dimensional material; Or / and, the preparation of the core-shell composite structure, the amino modified conductive two-dimensional material is reacted with MoO4 in the Mo source under acidic conditions 2- Through electrostatic interaction and hydrogen bonding, they gather around the conductive two-dimensional material, thereby uniformly growing MoS2 nanosheets on the surface of the conductive two-dimensional material to form a core-shell composite structure; Or / and, the thioctic acid ionic liquid is an ionic liquid formed by thioctic acid and 1-ethyl-3-methylimidazolium chloride; Or / and, the conductive two-dimensional material is selected from GO, rGO, Ti3C2T x 、V2CT x 、Nb2CT x 、Ti2CT x and Mo2CT x Any one or two or more of the following.

3. The method for preparing the ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive according to claim 1 or 2, characterized in that: The method comprises the following steps: (1) aminosilane is mixed in an alcohol-water mixed solution under alkaline conditions, an aqueous solution of a conductive two-dimensional material containing hydroxyl groups on the surface of a few nanosheets is added, the reaction is carried out under reflux, and after the reaction is completed, post-processing is performed to obtain an amino-modified conductive two-dimensional material, and the amino-modified conductive two-dimensional material is dispersed in water to obtain an aqueous solution of the amino-modified conductive two-dimensional material; (2) mixing the aqueous solution of the amino-modified conductive two-dimensional material with a solution containing MoO4 2- The Mo source and thiourea reacted at 180±5 ℃ under acidic conditions to obtain a conductive two-dimensional material@MoS2 nanocomposite material; (3) The conductive two-dimensional material @MoS2 nanocomposite material and thioctic acid ionic liquid are ultrasonically dispersed in an aqueous solution at 30±5°C, and then stirred at room temperature to obtain an ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive.

4. The preparation method according to claim 3, characterized in that In step (1), the aminosilane comprises: KH550; or / and, in step (1), the alkaline condition is adjusted by using aqueous ammonia; Or / and, in step (1), the amount of KH550 and the conductive two-dimensional material containing hydroxyl groups on the surface of the few-layer nanosheet is 4 mL: 1200 mg; or / and, in step (1), the volume ratio of water to ethanol is 1:1; Or / and, in step (1), the volume ratio of KH550 to the alcohol-water mixed solution is 1:100; or / and, in step (1), the reflux temperature is 70°C; Or / and, in step (1), the conductive two-dimensional material containing hydroxyl groups on the surface of the few-layer nanosheet is selected from the few-layer nanosheet Ti3C2T; Or / and, in step (2), the acidic condition is adjusted by citric acid, the Mo source is Na2Mo2O4·2H2O, and the mass ratio of Na2Mo2O4·2H2O, thiourea and citric acid is 2.9~3.0:4.2~4.3:0.2~0.3; Or / and, in step (2), the Mo source is Na2Mo2O4·2H2O, and the mass ratio of the amino-modified conductive two-dimensional material to Na2Mo2O4·2H2O is 1:3.9-4.0; Or / and, in step (2), the reaction time is 24 h; or / and, in step (3), the method for preparing the thioctic acid ionic liquid comprises: dissolving 1-ethyl-3-methylimidazolium chloride in ethanol, dissolving sodium hydroxide or potassium hydroxide in an ethanol solution, mixing the two solutions together, stirring at room temperature, removing sodium chloride or potassium chloride, and reacting with thioctic acid under stirring at room temperature to obtain the thioctic acid ionic liquid; Or / and, in step (3), the mass ratio of the conductive two-dimensional material @MoS2 nanocomposite material and the thioctic acid ionic liquid is 1:1; Or / and, in step (3), stirring at room temperature for 24 h.

5. Use of the ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive as claimed in claim 1 or 2 in conductive grease.

6. An ionic liquid modified Ti3C2T x @MoS2 conductive polyurea grease, characterized by: The conductive polyurea grease comprises: the ionic liquid-modified conductive two-dimensional material @MoS2 lubricating additive as claimed in claim 1 or 2, and polyurea grease.

7. The ionic liquid modified Ti3C2T according to claim 6 x @MoS2 conductive polyurea grease, characterized by: The mass fraction of the ionic liquid modified conductive two-dimensional material @MoS2 lubricating additive is 0.3-2.0 wt%; Or / and, the polyurea grease is a polyurea grease with a thickener mass fraction of 8%; Or / and, in the polyurea grease, the thickener is a polyurea formed by the reaction of 4,4'-methylenebis(phenyl isocyanate) with cyclohexylamine and octadecylamine; Or / and, in the polyurea grease, the base oil comprises any one or more of PAO8, PAO10 and PAO20.

8. The ionic liquid modified Ti3C2T3 according to claim 6 or 7 x @The preparation method of MoS2 conductive polyurea grease is characterized in that: The method includes: The conductive two-dimensional material @MoS2 lubricating additive modified by the ionic liquid as claimed in claim 1 or 2 is added to the polyurea grease, stirred at room temperature, and ground to obtain the ionic liquid modified Ti3C2T x @MoS2 conductive polyurea grease.

9. The preparation method according to claim 8, characterized in that The preparation method of the polyurea grease comprises: 4, 4'-methylenebis(phenyl isocyanate) was added to PAO8 and stirred continuously at 60-70°C until completely dissolved to obtain mixture A. Cyclohexylamine and octadecylamine were added to the base oil and stirred thoroughly at 80-90°C to obtain a uniform mixture B. Mixture B was quickly added to mixture A and reacted at 90°C. The reaction system was then heated to 110-120°C and maintained at this temperature. The temperature was then increased to 140-150°C and maintained. After the reaction was completed, the mixture was rapidly cooled and ground to obtain a polyurea grease.

10. The ionic liquid modified Ti3C2T3 according to claim 6 or 7 x @Application of MoS2 conductive polyurea grease in bearings.

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